MP: FIX replicant walk-entry floor -- gate on standSpeed not walkStrideLength (task #50)

The prior floor gated on walkStrideLength*0.5, but walkStrideLength is a
stride METRIC (~22.0), not the walk velocity (~6.1) -- so the condition
sd > 11 was never true for a walking peer and the floor never fired. The
replicant's derived speedDemand (== actual velocity 6.13) sits BELOW
standSpeed (6.83), so the leg SM's stand->walk gate (standSpeed < demand)
never tripped and the peer slid forward in the Standing pose.

Gate on standSpeed instead: floor the demand to standSpeed*1.05 when the
peer is clearly walking (demand in (standSpeed*0.5, standSpeed*1.05)).
Verified live: uvel=6.13 -> spd=7.169 floored, legState enters 5 (walk)
on frame 1 with no Standing-pose slide. standSpeed=6.8277 confirmed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

game/reconstructed/mech4.cpp

@@ -1968,8 +1968,10 @@ void
 				// so the CADENCE still matches the actual travel (no foot-slip).  Reverse
 				// needs no floor -- its entry gate is `commandedSpeed < ZeroSpeed`, which
 				// any negative demand already trips.
-				if (sd > walkStrideLength * 0.5f && sd < standSpeed * 1.1f)
-					sd = standSpeed * 1.1f;
+				// (CORRECTED threshold: walkStrideLength is a STRIDE metric ~22, NOT
+				// the walk velocity ~6.1 -- gate on standSpeed, the actual gate value.)
+				if (sd > standSpeed * 0.5f && sd < standSpeed * 1.05f)
+					sd = standSpeed * 1.05f;
 				replMppr->speedDemand = sd;
 				// REPLICANT TURN-STEP (user-reported: a turning peer
 				// statue-rotates while the local mech steps): the leg SM's
@@ -2060,6 +2062,8 @@ void
 							<< " spd=" << replMppr->speedDemand
 							<< " legState=" << (int)legStateAlarm.GetLevel()
 							<< " legFrm=" << legAnimation.currentFrame
+							<< " standSp=" << standSpeed
+							<< " walkStr=" << walkStrideLength
 							<< " nu-lp=" << (nextUpdate.ticks - lastPerformance.ticks)
 							<< " dt=" << dt << "\n" << std::flush;
 				}